In the third chapter of the Book of Jonah, Jonah finally reaches Nineveh, and starts preaching repentance and reformation to the people there. And... they listen! Even the King of Assyria listens!

The inner meaning of the story is pretty close to the surface here, and there's important symbolism. Swedenborg summarizes the chapter's meaning in this one sentence:

"The nations, hearing from the Word of God about their sins, and that they would perish, were converted after repenting, and were heard by the Lord, and saved." (The Inner Meaning of the Prophets and Psalms 213)

Rev. George McCurdy, in his exegesis of this chapter, offers this summary:

The great city of Nineveh has many spiritual representations. The world saw Nineveh as a mighty nation, but in the eyes of the Lord, it represented the shallowness and weakness (death) of false doctrines, contrived beliefs confirmed by the proprium (self love), the fallacies of the senses, and the unenlightened understanding that spawns spiritual ignorance.

The Lord’s mercy and love for all prompted Him not only to send His message to Nineveh, but to ensure that it would be preserved for eternity. Jonah’s call to "arise and go" preach to Nineveh is a call for spiritual renewal. It is a call for repentance. The fasting, sackcloth, and ashes symbolize a call to be aware that "where there is no truth, there is no church."

Where the Word is closed, and not loved, there is a loss of conjunction with the Divine resources. The fasting of man and beast symbolizes a need for the spiritual and natural appetites to come to the Lord for that "bread which comes down from heaven." The Ninevites giving up their natural food and drink represents their turning away from "as-of-self" concepts and reminds all who read and hear the Word of the Lord to rely on heavenly manna.

"Why do you spend money for what is not bread, and your wages for what does not satisfy? Listen carefully to Me and eat what is good, and let your soul delight itself in abundance…" (Isaiah 55:2)

The king sitting in ashes and mourning represents a sorrowful attitude toward "the remains of the fire of self-love." Repentance involves self-examination, making oneself guilty for the sins and evils committed, asking the Lord for His help, and desiring to attain a new life.

As we mull over this concept, think about the Lord’s preaching on earth. As He went about His mission, He often used these words: "You have heard it said of old… but I say unto you…" Putting aside human traditions and taking on the Lord’s teachings is an ongoing effort. Jonah was told to preach the words of the Lord. He was not to make things up from his memory. He was to be a true and faithful prophet of the Lord’s ways.

Here's a link to an interesting (audio) sermon on this chapter, by Rev. Todd Beiswenger.

Rev. Martin Pennington suggests two explanatory passages from Swedenborg's theological writings:

"Forty days means a period of temptation combats or severe change." (Arcana Coelestia 730)

"A fast represents those who are in a state of unhappiness when good is no longer joined to the truths." (Arcana Coelestia 9182[10])

Other references of interest listed by Rev. McCurdy include:

"As ‘forty’ signified what is full or complete… forty signifies what is complete in respect to instruction and influx… for this reason it was said by Jonah to the Ninevites that ‘the city would be overthrown after forty days" (Jonah 3:4) (Arcana Coelestia 9437[2])

"By being clothed in sackcloth is signified mourning on account of the vastated truth in the church; for garments signify truths; and therefore, to be clothed in sackcloth, which is not a garment, signifies mourning that there is no truth; and where there is no truth, there is no church." Jonah 3:5-6 is cited. (Apocalypse Revealed 492)

"…the rite of putting sackcloth on the loins to testify…mourning may be seen from the historic and prophetic parts of the Word, as in… Jonah 3:5-8… for a sign representative of mourning over the evil on account of which Nineveh was to perish; thus over destroyed good." (Arcana Coelestia 4779[2])

"From the signification of garments it is also manifest why they rent their garments, when any one spoke against the Divine truth of the Word… and why, on account of transgressions against Divine truths, they put off their garments, and put on sackcloth." Jonah 3:5, 6, and 8 are cited. (Apocalypse Revealed 166)

"That ‘ashes’ denote falsity, may be confirmed from passages where another word for ‘ashes (cinis)’ is used, for these ashes have a like origin…" Jonah 3:6 is cited. (Arcana Coelestia 7520)

"…by ‘ashes’ in the opposite sense, namely, what is condemned that remains after the burning from the fire of self love. This is signified by ‘the ashes’ which they carried on the head, and in which they rolled themselves when bewailing their sins." Jonah 3:6 is cited. (Arcana Coelestia 9723)

"In the spiritual sense by kings those who are in truths are signified, by the great ones those who are in goods, by the rich those that are in the knowledge of good, by the mighty they that are in erudition, by servants they that are in such things from others, and thus from memory, and by freemen they that are in such things from themselves…" Jonah 3:7 is cited. (Apocalypse Revealed 337)

"The interior good and also the interior evil…are signified by ‘man,’ are those which are of the intention or end, for the intention or end is the inmost of man; but the exterior good and also the exterior evil which are signified by ‘beast,’ are those which are of the thought, and of the consequent action when nothing stands in the way…By ‘beast,’…in respect to the external or natural man, a man is nothing else than a beast, for he takes delight in the like cupidities and pleasures, as also in the like appetites and sense…Therefore… from a holy rite it was commanded by the king of Nineveh, that both man and beast were to fast, and were to be covered with sackcloth (Jonah 3:7, 8)." (Arcana Coelestia 7523)

"… in the spiritual world a man’s affections appear at a distance like beasts… and beasts, viewed in themselves, are nothing but forms of natural affections… By man and beasts together is signified man as to spiritual and natural affection, in the following passages… Jonah 3:7, 8…" (Apocalypse Revealed 567)

"Here ‘webs’ and ‘garments’ are predicated of things of the understanding, that is, of the thought; ‘iniquity’ and ‘violence,’ of things of the will, that is, of works. In Jonah 3:8… the ‘evil way’ is predicated of falsities, which are of the understanding; and ‘violence,’ which are of the will." (Arcana Coelestia 623[2])

"…the ‘wrath of anger’ is attributed to Jehovah, and consequently ‘repentance.’" (Arcana Coelestia 588[2])

"…the Word is such in the sense of the letter, it may be evident that it cannot be understood without doctrine. But let examples illustrate this. It is said that Jehovah repenteth (Jonah 3:9; 4:2), and it is also said that Jehovah repenteth not (Num. 23:19…): without doctrine these statements do not agree." (Teachings Regarding the Sacred Scripture 51)

"In these passages (Jonah 3:9,10) Jehovah is said to have ‘repented,’ when yet it cannot be that He repents, because He knows all things before He does them; from which it is evident that by ‘repenting’ is signified mercy." (Arcana Coelestia 10441[2-4])

Finally, here's a link to Rev. McCurdy's study guide for the Book of Jonah, which is available for free as a .pdf, for your use.

7778. 'And all the firstborn in the land of Egypt will die' means the damnation of faith separated from charity. This is clear from the meaning of 'dying' as damnation, dealt with in 5407, 6119; and from the meaning of 'the firstborn' as the Church's faith through which charity comes, dealt with in 352, 2435, 6344, 7035. But 'the firstborn in the land of Egypt' is faith devoid of charity, about which see above in 7766.

[2] As regards faith devoid of charity, there is more to be said. Faith that is devoid of charity is not faith but merely knowledge of such things as constitute faith. For the truths of faith look to charity as their ultimate end in view, and later on proceed from charity as their first end in view. From this it is evident that the things which constitute faith do not exist with those who have no charity, even though they have a knowledge of the truths of faith, as is well known. This knowledge is what they call faith. And when they use the facts they know about the truth and good of faith to support falsities and evils, they no longer have the truths and forms of the good of faith because these come to be like the falsities and evils that such truths and forms of good serve. For now the very falsities and evils which they support are seen in them.

[3] Things that constitute genuine faith look upwards to heaven and the Lord, whereas those that constitute faith separated from charity look downwards - and when they support evils and falsities - to hell, from which too it is evident that faith separated from charity is not faith. All this goes to show what is meant by the damnation of faith separated from charity, that is to say, of the truth of faith when falsified and the good of faith when adulterated. For when truth has been falsified it is no longer truth but falsity, and when good has been adulterated it is no longer good but evil; and faith itself is no longer faith composed of truth and good but of falsity and evil, no matter what it looks and sounds like to outward appearance. Furthermore, and this is an arcanum, the character of anyone's faith is determined by the character of his life. If therefore his life is damned, so is his faith; for it is a faith composed of falsity when his life is a life of evil. It is not apparent in the world that this is so, but it is made plain in the next life. When the evil in that life are deprived of the truth and good they know there then emerge from evils the falsities which have lain hidden with those people.

[4] With some evil people a certain kind of conviction exists that the truth of faith is the truth; and this conviction too is thought to be faith. But it is not faith since it is induced by the intent to make it serve as the means by which wealth, important positions, and reputation can be acquired. As long as the truths they know are serving as the means to that end they love them for the sake of an evil intent. But when they no longer serve in that way they are abandoned, indeed are regarded as falsities. The term 'persuasive faith' is used to describe this kind of conviction, and it is what is meant by the Lord's words in Matthew,

Many will say to Me on that day, Lord, Lord, did we not prophesy though Your name, and through Your name cast out demons, and do many mighty works in Your name? But then I will confess to them, I do not know you; depart from Me, you workers of iniquity. Matthew 7:22-23.

The same kind of faith is also meant by 'lamps without oil' with the five foolish virgins, who also said, Lord, Lord, open to us. But He replying said, Truly, I say to you, I do not know you. Matthew 25:11-12.

The truths of faith are meant by 'lamps', and the good of charity by 'oil', so that 'lamps without oil' are truths of faith devoid of the good of charity.